White 20 threatens, with the support of 12, to invade at E and
destroy potential black territory.

Black 21: A good play. It promises future attacks on white 20.

White 26: Since Black already has a stone at 21, White doesn't play
27. Black would then answer with F, and although 22 and 24 would live,
20 would stand alone and hard pressed. For this reason white first
secures the corner with 26, thus abandoning 22 and 24 for the present,
hoping for an opportunity to save them later.

Black 29: Black would like to play at 20 (see
handicap joseki article[4]), but as this is already occupied the best
move is 29. G is used normally, but as is there 29 is better as it captures both stones.

Black 31: A typical attack by white, reducing the black potential,
answered in one of the best ways, separating the two white stones.

Black 33: A very good play in the circuumstances. White threatened
to play G and then to connect to 32 or . After 33 the white stones have lost all
chances of survival.

Black 35: A play strongly attacking the white stone, possibly
better at 43 which is simpler, for then white H, black 42, securing the
corner and attacking the white stones strongly.

Black 39: The normal play. Otherwise white will be able to connect
through the black position.

Black 41: The beginner, usually afraid to start a ko fight, would
probably have played J instead. This would have been a poor play, as
white would reply at 42 and even though the black group lives, it is worth
very little, see Dia 2. It is then best for Black to play 41 and engage
in the ko fight. Should he lose the ko, he is bound to gain an advantage
elsewhere.

White 44: Black must answer this, or else white (playing G) would
save his stones near there, and threaten black on the right side.

Black 47' could also have threatened at 58 or 49, but 47 is a safer
play, since it not only secures his own stones but also cuts apart
white's.

White 48 takes because black has many more ko threats.

Black 49 continues the attack started with 47. He has lost the ko,
but was able to make the important plays 47, 49 and generally made out
well.

White 50: If white had connected at 51 instead, black's reply at K
would have cut white off completely.

Black 51: This play doesn't seem necessary at this time. However,
since black has no weak position to defend, the play is a good one as it
prevents possible future developments of an unpleasant nature.

White 52: White wants to see how Black will react before deciding
on his future plans.

Black 53: This is the correct answer. Black can play this because
he has already.

White 54: In this way White still brings use from the sacrificed
stone 52.

White 58: There was the constant threat that black might occupy 58,
then white L, black M and white would have been very hard pressed here.

Black 59: A good play as white is forced to answer, to make sure
that black cannot play 61' at 60 and seriously endanger the life of the
white group.

Black 61: There was the threat that white might play N, black P,
white Q reducing the large black potential.